By: Vivian H. Lyons, Emma L. Gause, Keith R Spangler, et al.

Importance: Firearm violence is a leading public health crisis in the US. Understanding whether and how ambient temperature is associated with firearm violence may identify new avenues for prevention and intervention.

Objective: To estimate the overall and regional association between hotter temperatures and higher risk of firearm violence in the US.

Design, setting, and participants: This cross-sectional study used distributed lag nonlinear models, controlling for seasonality and long-term time trends by city and pooled results overall and by climate region. The most populous cities in the US with the highest number of assault-related firearm incidence (ie, shootings) from 2015 to 2020 were analyzed. Data analysis was performed from October 2021 to June 2022.

Exposures: Maximum daily temperature by city.

Main outcomes and measures: The primary outcome was the number of assault-related firearm shootings by city.

Results: A total of 116 511 shootings in 100 cities were included in this analysis. The pooled analysis estimated that 6.85% (95% CI, 6.09%-7.46%) of all shootings were attributable to days hotter than city-specific median temperatures. This equates to 7973 total shootings (95% CI, 7092-8688 total shootings) across the 100 cities over the 6-year study period, although the number of total persons injured or killed would be higher. Estimated risk of firearm incidents increased almost monotonically with higher temperatures, with a local peak at the 84th percentile of the temperature range corresponding to a relative risk of 1.17 (95% CI, 1.12-1.21) compared with the median temperature. However, even moderately hot temperatures were associated with higher risk of shootings. Although significant, there was low heterogeneity between cities (I2 = 11.7%; Cochran Q test, P = .02), indicating regional or climate-specific variation in the daily temperature and incident shootings relationship.

Conclusions and relevance: These findings underscore the importance of heat adaptation strategies broadly throughout the year to reduce shootings, rather than focusing on only the hottest days.

JAMA Netw Open. 2022 Dec 1;5(12):e2247207. doi: 10.1001/jamanetworkopen.2022.47207. PMID: 36525273; PMCID: PMC9856408.

By Elinore J. Kaufman; Douglas J. Wiebe; Ruiying Aria Xiong

Importance  Firearm injury research in the US has focused on fatal injuries. The incidence and epidemiologic factors associated with nonfatal firearm injuries are less understood.

Objective  To evaluate estimates of incidence and trends over time of fatal and nonfatal firearm injuries.

Design, Setting, and Participants  A cross-sectional, ecologic study was conducted using data throughout the US from 2009 to 2017. Data on fatal injuries from the Centers for Disease Control and Prevention were combined with national data on emergency department visits for nonfatal firearm injury from the Nationwide Emergency Department (ED) sample. Data analysis was conducted from August 2019 to September 2020.

Exposures  Firearm injuries identified with International Classification of Diseases external cause of injury codes and categorized by intent of injury, age group, and urban-rural location.

Main Outcomes and Measures  Incidence, case fatality rate, and trends over time of firearm injury according to intent, age group, and urban-rural location.

JAMA Intern Med. 20210 181(2): 1–8

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